JPH02256469A - Fastening tool for stud bolt - Google Patents

Abstract

PURPOSE:To simply remove a fastening tool with a very small force by freely separating contact sections of a torque transmission mechanism from each other when a stud bolt is to be removed after it is fastened. CONSTITUTION:When a drive shaft 5 is rotated in the opposite direction after a stud bolt is fastened, contact sections of a torque transmission mechanism 10 are separated from each other, thus a screw shaft section 6 is loosened by applying the rotary torque slightly smaller than the rotary force in the bolt fastening direction applied to a cylinder from a screw shaft section 6 to the drive shaft 5. When this screw shaft section 6 is rotated by the required angle, the torque transmission mechanisms 10 are brought into contact with each other, the cylinder 2 is rotated together with the screw shaft section 6, and a fastening tool is removed from the stud bolt.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a stud bolt fastener used for tightening a stud bolt.

[Conventional technology]

The method of implanting the stud bolt is as shown in Figure 12.
A method of screwing a cap nut 60 onto the end of the stud bolt (B) and engaging a torque wrench with the cap nut 60 to rotate it, and a method of rotating the stud bolt as shown in FIG. There has conventionally been a method in which the nuts 61 and 62 are threadedly engaged, and the other nut 62 is tightened while one nut 61 is prevented from rotating.

[Problem to be solved by the invention]

By the way, in any of the above methods, when removing the cap nut 60 and the nuff 61, 62, a tightening force (fixing force) approximately equal to the tightening force required to tighten the stud bolt B is applied to each of the cap nut 60 and the nut 62. There is a disadvantage that it is necessary to apply loosening force, and removal is time-consuming.

In addition, in the method using two nuts 61 and 62, when loosening it, it is necessary to engage one nut 61 with a spanner or the like to prevent it from rotating, so it is difficult to use a moving tool such as an electric tool or an air-powered tool. There is a safety issue when removing using the

SUMMARY OF THE INVENTION Therefore, the present invention aims to solve the above-mentioned inconveniences and to provide a fastener for a stud bolt that can be removed very easily after tightening the stud bolt. This is a major issue.

[Means to solve the problem]

In order to solve the above problems, in the present invention, a first internal thread to which a stud is screwed and a second internal thread are provided in the axial direction of the cylinder on the inner circumferential surface of the cylinder. A threaded shaft portion provided at the tip of the drive shaft is screwed into the female thread of No. 2, and a screw shaft portion provided at the tip of the drive shaft is inserted between the drive shaft and the cylindrical body, so that when the drive shaft is rotated by a predetermined angle relative to the cylindrical body, a A torque transmission mechanism is provided to transmit the rotation of the drive shaft to the cylindrical body by engaging with the cylindrical body, and converts the rotational torque in the bolt tightening direction transmitted from the screw shaft portion to the cylindrical body into the rotational torque required for tightening the stud bolt. They adopted a configuration that provided means for making it even smaller.

Here, as a method for making the rotational torque in the bolt tightening direction transmitted from the drive shaft to the cylinder body smaller than the rotational torque required for tightening the stud bolt, the frictional resistance between the second female thread and the screw shaft is reduced. , a method of making the frictional resistance between the first screw and the stud bolt smaller than that of the first screw, a method of making the lead angle of the second female screw larger than a lead angle of the first female screw, and a method of making the average diameter of the second female screw smaller than that of the first female screw. A method of making the diameter smaller than the average diameter of the female thread, a method of making the second female thread a square thread, and a method of making the first female thread a triangular thread can be adopted.

In order to further facilitate the removal of the stud bolt, an axial insertion hole is formed in the threaded shaft portion of the drive shaft, and the shaft member is slidably inserted into the insertion hole.
A configuration was adopted in which a thrust bearing that receives the thrust reaction force of the shaft material is incorporated inside the drive shaft.

In addition, for the same purpose as above, a friction body that can come into contact with the head of the stud bolt is incorporated in the front side of the drive shaft, and the friction body is prevented from rotating relative to the cylinder body, and the axis of the cylinder body is We adopted a structure in which it was supported so that it could be moved freely in both directions.

[Effect]

In order to tighten the stud bolt using the tightening tool configured as described above, the stud bolt is screwed into the first female thread while the torque transmission mechanism is in contact with it in the tightening direction. With the head of the bolt in contact with the tip of the drive shaft, screw the above-mentioned stud bolt into the screw hole of the member to be tightened, then rotate the drive shaft in the tightening direction, and the rotation will be matched with the screw shaft. The bolt is tightened by transmitting torque to the cylinder body from both the threaded engagement surface of the second female screw and the abutting portion of the torque transmitting mechanism.

After tightening the stud bolt, if the drive shaft is rotated in the opposite direction to the above, the contact parts of the torque transmission mechanism will separate from each other, so the rotation applied from the screw shaft to the cylinder body in the bolt tightening direction By applying a rotational torque slightly smaller than the force to the drive shaft, the screw shaft loosens, and when the screw shaft rotates the required angle, the torque transmission mechanisms come into contact with each other and the cylinder rotates together with the screw shaft, causing the implant to be removed. The fastener can be removed from the bolt.

〔Example〕

Embodiments of the present invention will be described below with reference to FIGS. 1 to 1).

1 and 2 show a first embodiment of a fastener according to the present invention. A cylindrical body 2 having a flange 1 has a first internal thread 3 and a second internal thread 4 on the inner peripheral surface. is provided in the axial direction, and the first internal thread 3 is threadedly engaged with the stud.

A screw shaft portion 6 provided at the tip of the drive shaft 5 is screwed into the second female thread 4 . At the tip of this screw shaft portion 6, a small diameter shaft portion 7 with a pointed tip is provided. In addition,
The tip of the small diameter shaft portion 7 may be formed into a spherical surface.

A torque transmission mechanism 10 is provided between the cylindrical body 2 and the drive shaft 5, which transmits the rotation applied to the drive shaft 5 to the cylindrical body 2.

Here, the torque transmission mechanism 10 has a radial pin insertion hole 12 formed in a flange 1 provided on the lower outer periphery of the drive shaft 5, and pins both ends of a transmission pin 13 inserted into the pin insertion hole 12. An engagement pin 14 is provided on the upper surface of the flange 1 of the cylindrical body 2 so as to protrude outward from the insertion hole 12 and to which both ends of the transmission pin 130 can come into contact.

As shown in FIG. 7, a general formula for screwing the stud B into the screw hole 21 of the member to be tightened 20 will be described below. In this general formula, the frictional force between the head of the stud B and the small diameter shaft portion 7 of the drive shaft 5 is ignored because it acts equally on both in this embodiment. In FIG. 7, the force F that turns the implantable pole B is expressed as F-Wtan (φ. 10.)...■.

Further, the loosening force F' is expressed as F'=Wtan(φ.-〇.)...■.

Here, θ is the thread lead angle of stud B, φ,
is the friction angle, and W is the reaction force received from the threaded surface of the screw hole 21.

If the average diameter of the stud B is d, then the rotational torque T0 required to turn the stud B and the rotation torque T,' required to loosen the stud B are: e T,'-F'・T...■ It is expressed as.

From the above ■ and formula 0, 7,''-aLaa (# *-θ.) -・-・
− becomes ■.

Therefore, when the stud B is screwed into the first female thread 3 of the cylindrical body 2 and the head of the bolt B is brought into contact with the small diameter shaft portion 7 of the screw shaft portion 6, the screwing operation of the stud bolt B is performed. It is necessary to apply a rotational torque T expressed by the above equation 0 to the cylinder body 2.

In the fastener shown in FIG. 1, by rotating the drive shaft 5, the rotational force of the drive shaft 50 is transferred from the engagement portion of the transmission pin 13 and the engagement pin 14 and the screw engagement surface of the screw shaft portion 6 to the cylinder. transmitted to body 2. The rotational torque T1 transmitted from the screw shaft portion 6 to the cylindrical body 2 is as in the above formula 0.

In addition, θ is the lead angle of the screw of the screw shaft portion 6, φ is the friction angle, d is the average diameter of the screw shaft portion 6, W is the reaction force (axial force) received from the screw surface, and 0 reaction force W is , is equal to the reaction force of stud B.

The rotational torque TI of the above-mentioned type 0 transmitted from the threaded engagement surface of the screw shaft portion 6 is made smaller than the rotational torque T0 required for tightening the stud B.

In other words, the following relational expression is established. In order to establish this relational expression, at least one of the average diameter d and the % friction angle φ of the thread of the screw shaft portion 6 should be made smaller than the average diameter daSMl friction angle φ of the thread of the stud B. Alternatively, the thread of the screw shaft portion 6 may be a square thread, and the thread of the stud B may be a triangular thread.

In order to reduce the friction angle φ, it is possible to form a film of a solid lubricant such as molybdenum disulfide on the thread of the screw shaft portion 6, or to treat it with fluorine.

In FIG. 1, 8 is a cover that covers the coupling part between the cylinder body 2 and the drive shaft 5, and S is a cover that prevents dust from entering the screw engagement part between the second female screw 4 and the screw shaft part 6. It is a dustproof seal that prevents dust.

The fastener shown in the first embodiment has the above structure, and when tightening the stud B, the torque transmission bottle 13 and the engagement pin 14 are aligned in the tightening direction as shown in FIG. In this state, screw the stud B into the first female thread 3 of the cylindrical body 2, bring the head of the stud B into contact with the tip of the small diameter shaft part 7, and then cover the stud B. The screw is engaged with the screw hole 21 of the tightening member 20 to apply a rotational force to the drive shaft 5 in the tightening direction.

As a method of imparting rotational torque, a method of forming a radial hole 5' in the drive shaft 5 and inserting a rod into the hole 5' to rotate it, or a method of rotating it using a movable crab tool can be adopted. I can do it.

Due to the rotation of the drive shaft 5 in the tightening direction, the rotation is transmitted to the cylindrical body 2 by the contact between the transmission pin 13 and the engagement pin 14 during initial tightening. Therefore, the rotation of the cylinder 2 is transmitted to the stud B, and the stud B is deeply screwed into the screw hole 21.

When the tip of the implantable pole) B comes into contact with the bottom of the screw hole of the member to be tightened 20 and the tightening force gradually increases, the implantable pole) B
The cylindrical body 2 moves relative to the cylindrical body 2, and the small-diameter shaft portion 7 comes into even stronger pressure contact with the head surface of the stud B.

When the pressure contact force increases, the screw shaft portion 6 and the second female screw 4
The contact force increases on the threaded engagement surface, and the rotation of the drive shaft 5 is transmitted to the cylindrical body 2 from the threaded engagement surface.

At this time, the rotational torque transmitted from the screw retaining surface to the cylindrical body 2 is smaller than the rotational torque required to tighten the stud B, so the insufficient rotational torque is transferred to the transmission pin 13 and the engagement pin 14. It is transmitted from the contact portion to the cylinder body 2.

Therefore, the cylinder body 2 is connected to the screw shaft portion 6 and the torque transmission mechanism 1.
Torque is transmitted from both of the retaining portions of the cylindrical body 2 and the cylindrical body 2 rotates, and the implanted pole B is strongly tightened by the rotation of the cylinder body 2.

After tightening the stud bolt B, when the drive shaft 5 is rotated in the opposite direction, the transmission pin 13 is moved to the engagement pin 14.
move away from

Therefore, when removing the fastener, it is only necessary to apply a slightly smaller rotational torque to the drive shut 5 than the rotational torque applied to the cylinder body 2 from the screw shaft 6 when tightening the bolt; As a result, the screw shaft portion 6 is loosened, and when the screw shaft portion 6 is rotated by a predetermined angle, the transmission bottle 13
engages with the engagement pin 14, and due to this engagement, the cylindrical body 2 is returned and removed from the implantable pole (B).

Therefore, the fastener can be removed with very little rotational force.

3 and 4 show a second embodiment of the fastener according to the present invention. In this embodiment, a transmission pin 13 is attached to a protrusion 15 provided on the flange 1) of the drive shaft 5. Attachment: A torque transmission mechanism 10 is used in which a projection 16 is formed on the outer periphery of the cylindrical body 2, and the rotation of the drive shaft 5 is transmitted to the cylindrical body 2 by engagement of the projection 16 and the transmission pin 13.

The other configurations and operations are the same as those in the first embodiment, so their explanations will be omitted.

5 and 6 show a third embodiment of the fastener according to the present invention. In this embodiment, a bottom plate 31 is attached to the bottom of a cover portion 30 provided at the lower end of a drive shaft 5. An insertion hole 32 is formed in the axis of the threaded shaft portion 6' which is fixed to the bottom plate 31 and is threadedly engaged with the second female thread 4 of the cylinder body 2.
A shaft member 33 is slidably inserted into the insertion hole 32.

Further, a disc 34 is provided at the end of the shaft member 33 located inside the cover part 30, and a thrust bearing 35 that receives the thrust reaction force of the disc 34 is incorporated into the cover part 30.

Furthermore, a protruding part 36 is formed on the lower surface of the cover part 30, and a bottle 37 is provided protrudingly on the outer periphery of the cylindrical body 2, and the rotation of the drive shaft 5 is controlled by the engagement between the bottle 37 and the protruding part 36. Since the other configurations are the same as those of the first embodiment, the same parts are given the same reference numerals and the explanation will be omitted.

The fastener configured as described above limits the ability of the cylinder 2 to be fastened to the stud B by engagement between the tip of the shaft member 33 and the head of the stud B. At that time, by supporting the thrust reaction force acting on the shaft member 33 with the thrust bearing 35, the drive shaft 5
When loosening the drive shaft 5, since there is almost no effect of the frictional force between the tip of the shaft member 33 and the head of the stud B, the drive shaft 5 can be loosened with a smaller rotational force.

8 to 10 show a fourth embodiment of the fastener according to the present invention. In this embodiment, the cylindrical body 2 consists of three parts: a tip ring 41, an intermediate ring 42, and a rear end ring 43. The tip ring 41 and the rear end ring 43 have screws 44
and are held in a connected state by a pin 45 embedded in the joint.

A first internal thread 3 is formed on the inner periphery of the tip ring 41 . Further, a second internal thread 4 is formed on the inner periphery of the rear end ring 43.

Further, the drive shaft 5 is rotatably supported by a bearing 46 incorporated inside the tip ring 41 and the rear end ring 43, and a torque transmission mechanism 10 for transmitting the rotation of the drive shaft 5 to the cylinder body 2 is provided at the rear end. It is provided between the ring 43 and the ring 43.

As shown in FIG. 9, the torque transmission mechanism 10 has a circumferentially long pin hole 47 formed in the rear end ring 43, and a pin 48 inserted into the pin hole 47 is fixed to the drive shaft 5.

Further, a friction body 49 is incorporated in the front side of the small diameter shaft portion 7. As shown in FIG.
An axial groove 51 into which the friction plate 49 is inserted is formed, and the friction plate 49 is supported by the groove 51 and the protrusion 50 so as to be slidable in the axial direction, and is prevented from rotating relative to the tip ring 41.

With the above configuration, when the cylindrical body 2 is threadedly engaged with the stud B and the drive shaft 5 is rotated in the tightening direction,
A friction body 49 comes into contact with the head of the stud B. In this state, when the stud l-B is screwed into the screw hole and the drive shaft 5 is further rotated in the tightening direction, the stud B is screwed in.

At this time, the rotational force transmitted from the cylindrical body 2 to the stud B is the frictional force between the first female thread 3 and the stud 3, and the contact portion between the head of the stud B and the friction body 49. Frictional force, stud bolt B is decomposed into contact force (axial force) that abuts the friction body 49, and the cylinder body 2 is fixed to the stud B. Its adhesion strength is
Implant pol) is proportional to the resistance acting on B.

Therefore, the axial force is reduced by the amount decomposed into the frictional force of the contact portion between the head of the stud B and the frictional body 49.

In this way, by applying rotational force to the stud B from both the first female thread 3 and the friction body 49, the axial force acting on the threaded engagement portion of the first female thread 3 and the stud pole H is reduced. is reduced by the proportion that the frictional force on the head of the stud B is greater than in the embodiment shown in FIG. This axial force is equal to the axial force acting on the threaded engagement portion of the second female screw 4 and the threaded shaft portion 6.

Therefore, when tightening the stud bolt, the ratio of the rotational torque transmitted from the torque transmission mechanism 10 to the cylinder body 2 by the rotation of the drive shaft 5 and the rotational torque transmitted from the screw shaft part 6 to the cylinder body 2 is the first. The rotational torque transmitted from the screw shaft portion 6 to the cylindrical body 2 can be made smaller than that of the first embodiment.

Therefore, after the stud B is tightened, the fastener can be removed from the stud B with an extremely small rotational force.

In addition, by making the frictional resistance at the contact portion between the friction body 40 and the small diameter shaft portion 7 smaller than the frictional resistance at the contact portion between the friction body 49 and the stud pole B, the tightening tool is removed from the stud bolt B. The loosening force can be further reduced.

1) As shown in the figure, a spacer 52 is installed between the small diameter shaft portion 7 and the friction body 49, a thrust roller 53 is installed between the spacer 52 and the friction body 49, Shaft part 7
The mutual rotational resistance may be reduced to reduce the loosening force when removing the fastener.

In the embodiment shown in FIG. 8, an engaging portion 54 is provided on the outer periphery of the tip of the cylindrical body 2 to which a wrench such as a spanner can be engaged.

The formation of the retaining portion 54 allows the stud bolt to be removed using the fastener according to the present invention. The above-mentioned retaining portion 54 may be provided in the cylindrical body 2 of other embodiments.

When removing the stud B, be sure to remove the drive shaft 5.
is rotated in the loosening direction to bring the torque transmission mechanism 10 into contact in the loosening direction, and in this state, the rotation of the cylindrical body 2 causes the cylindrical body 2 to be threadedly engaged with the stud bolt B and tightened. The head of the stud B is seated on the friction body 49, and the cylindrical body 2 is rotated in the tightening direction to such an extent that the stud B does not rotate in the tightening direction.

After the above tightening, the drive shaft 5 is rotated in the additional tightening direction within a range where the torque transmission mechanism 10 does not come into contact with the tightening direction, and the drive shaft 5 is implanted into the screw retaining portion of the first female screw 3 and the implantable pole I-B. Generates an axial force that is greater than the axial force required to tighten Pole) H. Due to the generation of the axial force, the cylindrical body 2 is fixed to the implanted pole B.

After fixing, the stud B is rotated in the loosening direction by rotating the cylindrical body 2 in the loosening direction using a wrench engaged with the retaining portion 54. After removing the stud I-B, the drive shaft 5 is rotated in the loosening direction to remove the fastener from the stud B.

[Effects of the Invention] As described above, in this invention, when the stud bolt is tightened, the rotation of the drive shaft is caused by rotation of the screw shaft, the thread engagement surface of the second female thread, and the engagement portion of the torque transmission mechanism. When the stud bolt is removed after tightening, the contact parts of the torque transmission mechanism separate from each other, so when the fastener is removed, the torque is transmitted from the screw retaining surface to the cylinder. It is only necessary to apply a rotational force slightly smaller than the rotational force in the bolt fastening direction to the drive shaft, and the fastener can be easily removed with extremely small force.

In addition, an insertion hole is formed in the screw shaft of the drive shaft,
By supporting the shaft inserted into the insertion hole with a thrust bearing, and pushing the stud bolt with the shaft,
When loosening the drive shaft, the influence of the frictional force between the shaft member and the stud bolt can be almost ignored, and the drive shaft can be loosened with a smaller rotational force.

Furthermore, by incorporating the friction body on the front side of the drive shaft, the fastener can be removed from the stud bolt after installation with a smaller rotational force.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional front view showing a first embodiment of the fastener according to the present invention, FIG. 2 is a cross-sectional plan view of the same, and FIG. 3 is a second embodiment of the fastener according to the above. FIG. 4 is a plan view of the same, FIG. 5 is a longitudinal front view of a third embodiment of the fastener, FIG. 6 is a side view of the torque transmission mechanism, and The figure is a cross-sectional view of the stud bolt tightened using the fastener shown in the first embodiment, FIG. 8 is a longitudinal sectional front view showing the fourth embodiment of the same fastener, and FIG. is ■− in Figure 8.
1) is a sectional view taken along the line X-X in Fig. 8; 1) is a sectional view showing another means for reducing the rotational resistance of the drive shaft; 12th FIG. 18-II is a sectional view showing a conventional fastener. 2...Cylinder, 3...First
Female thread, 4...Second female thread, 5...
...Drive shaft, 6...Screw shaft,
10...Torque transmission mechanism, 32...
Insertion hole, 33... Shaft material, 35...
・Thrust bearing, 49...Friction body. Agent Kama Tabumi Figure 10

Claims (3)

[Claims] (1) A first female thread with which the stud is screwed and a second female thread are provided in the axial direction of the cylinder on the inner circumferential surface of the cylinder;
A screw shaft provided at the tip of the drive shaft is threadedly engaged with the female thread of the drive shaft, and when the drive shaft is rotated at a predetermined angle relative to the cylinder, the drive shaft and the cylinder are mutually connected. A torque transmission mechanism is provided to engage and transmit the rotation of the drive shaft to the cylindrical body, and the rotational torque in the bolt tightening direction transmitted from the screw shaft portion to the cylindrical body is smaller than the rotational torque required for tightening the stud bolt. A fastening tool for a stud bolt, characterized in that it is provided with a means for tightening the bolt. (2) An axial insertion hole is formed in the threaded shaft portion of the drive shaft, a shaft member is slidably inserted into the insertion hole, and a thrust bearing that receives the thrust reaction force of the shaft member is placed inside the drive shaft. A fastener for a stud bolt according to claim (1). (3) Incorporate a friction body that can come into contact with the head of the stud bolt on the front side of the drive shaft, prevent the friction body from rotating relative to the cylinder, and support it so that it can move freely in the axial direction of the cylinder. A fastener for a stud bolt according to claim (1).